5－13 years old children's understanding of inertia

Research on naïve physics investigates children’s intuitive understanding of physical objects, phenomena and processes. Children, and also many adults, were found to have a misconception of inertia, called impetus theory. In order to investigate the development of this naïve concept and the mechanism underlying it, four age groups (5-year-olds, 2nd graders, 5th graders, and 8th graders) were included in this research. Modified experimental tasks were used to explore the effects of daily experience, perceptual cues and general information-processing ability on children’s understanding of inertia. The results of this research are: 1) Five- to thirteen-year-olds’ understanding of inertia problems which were constituted by two ogjects moving at the same spped undergoes an L-shaped developmental trend; Children’s performance became worse as they got older, and their performance in the experiment did not necessarily ascend with the improvement of their cognitive abilities. 2) The L-shaped developmental curve suggests that children in different ages used different strategies to solve inertia problems: Five- to eight-year-olds only used heuristic strategy, while eleven- to thirteen-year-olds solved problems by analyzing the details of inertia motion. 3) The different performance between familiar and unfamiliar problems showed that older children were not able to spontaneously transfer their knowledge and experience from daily action and observation of inertia to unfamiliar, abstract inertia problems. 4) Five- to eight-year-olds showed straight and fragmented pattern, while more eleven- to thirteen-year-olds showed standard impetus theory and revised impetus theory pattern, which showed that younger children were influenced by perceptual cues and their understanding of inertia was fragmented, while older children had coherent impetus theory. 5) When the perceptual cues were controlled, even 40 percent 5 years olds showed the information-processing ability to analyze the distance, speed and time of two objects traveling in two different directions at the same time, demonstrating that they have achieved a necessary level to theorize their naïve concept of inertia.朴素物理学是指儿童在接受系统的科学教育以前，对于客观世界的各种物理实体、现象和过程的朴素认识。前人在该领域的研究发现，儿童（包括成人）对惯性运动普遍存在着一种被称为“冲量理论”的前科学概念。为了进一步考察这种朴素惯性概念的发展变化趋势以及与之相应的认知发展机制，本研究选取5岁学前儿童组、小学二年级（8岁）、五年级（11岁）和初一年级（13岁）儿童为研究对象，采用不同的任务变式，探查了日常经验、知觉因素以及一般信息加工能力对儿童惯性运动认知的影响。本研究得出的主要研究结果如下： 1） 5－13岁儿童在由两物体同作匀速直线运动构成的惯性系问题中，对惯性运动的认知成绩呈L型曲线（U型发展曲线前半部），即随着年龄增长儿童对惯性运动的认知越来越偏离科学概念，其预测成绩逐渐降低，表明儿童的认知成绩并不一定与认知能力同步递增。 2） 该认知发展曲线反映出不同年龄段的儿童使用不同策略来解决惯性运动问题：5－8岁年幼儿童利用“两点对准”的启发式策略来预测惯性运动，而11－13岁儿童则通过对各运动维度编码分析来解决运动问题。 3） 5－8岁儿童在有/无直接经验的题目上选择无显著差异，言语报告显示他们皆用“两点对准”策略做出预测；11－13岁儿童在两题目上选择有显著差异，表明未能自发地将日常观察和操作得来的惯性运动的知识经验用于无直接经验的问题中，他们在无直接经验情景中的选择表现出“冲量理论”。 4） 5－8岁年幼儿童对惯性运动题目的认知，主要集中于“垂直型”和“零散型”，而从11岁开始，“零散型”人数显著减少，“标准冲量理论型”和“修正冲量理论型”人数增多。 5） 排除情景中的知觉因素影响后，40％的5岁半学前儿童也表现出相应的信息加工能力，并能在水平和垂直两个方向上同时对惯性运动的距离、速度、时间等维度分别进行编码分析，具备了形成“冲量理论”的必要条件